Resistance unit.



PATENTED JULY 3, 1906.

H. HEATH. RESISTANCE UNIT. APPLICATION FILED JULY 13. 1905.

Inventor.

Harrg E Heath.

HARRY E. HEAT ELEOTRI inrnnr enric ii, OF LYNN, IVIASSACHUSETTS,ASSIGNOR TO GENERAL C COMPANY, A CORPORATION NElV YORK.

RESZSTANCE- nun".

i l'o. 825,21 1.

Specification of Letters Patent.

Patented July 3, 1906.

To (:15 whom it may concern:

Be it known that I, HARRY E. HEATH, a citizen of the United States,residing at Lynn, county of Essex, State of ltiiassachusetts,

have invented certain new and useful Im' provements in Resis t anceUnits, of which the following is a specification.

This invention relates to resistance units for electric circuits, andhas for its object the provision of a device of this character which islight, cheap to construct, and at the same time is thoroughly eiilcientand durable.

Many forms of resistance units are known to the electric art, one of theprincipal forms being what is known as the resistance grid. This form ofunit is objectionable by reason of its excessive weight and for manyother reasons well known to those skilled in the art. The object of, myinvention is to construct a unit which will take the place of the gridby overcoming the objections thereto, although its uses are not limitedto those of the grid, since it is well adapted to any of the ordinaryuses to which a resistance unit may be subjected. In carrying out myinvention I provide an insulating material, such as inicanite orasbestos, oi the size and shape desired. Upon this material as a core Iwind a strip of resistance material, such as sheet-iron, the windingbeing of course in an open spiral, so as not to short-circuit the turns.In order to lock the conductor in place on the insulating material,corrugate the sheet preferably in the direction of the length of thestrips. This not only secures the strips to the core, but gives rigidityin the direction oi-the corrugations to the unit as a whole.

My invention further consists in'the details of construction and in thearrangement and combination of elements hereinafter set forth,

and particularly pointed out in the claims annexed to and forming a partof this applicatron.

in the drawings, in which is illustrated one form. of my invention, Flure 1 is a plan view of my resistance unit. 1 ig. 2 is a side elevationthereof, and Fig. 3 is a section taken on the line 3 of 1 i .1.

Referring to t e drawings, 1 is a sheet of insulating material, such asmicanite or asbestos, the latter being prefaable, due to its cheapnessand flexibility.

2 is a resistance-conductor, such as sheet iron in the form of a stripspirally wound upon the insulating material, as shown in the drawings. Inow corrugate the sheet, so as to secprely lock the turns in place.These corrugations also increase the stiffness or rigidity of the unitand they ma run in any direction or in more than one irection, ifdesired. The terminals 3 are'secured to the ends of the conductor byrivet or any other well-known manner.

It will thus beseen that I have provided a resistance unit which isexceedin ly cheap and light and can be subjected to t e roughest usagewithout injury. The conductingstrips are secured to the insulatingmaterial without the aid of any rivets or any kindred devices, and themethod of production is of the simplest. The strip is simply wound uponthe insulating-sheet and passed through rollers to form corrugations.The unit, moreover, will stand high temperatures and will not crack whensubjected to sudden changes in temperature.

What I claim as new, and desire to secure by Letters Patent ol' theUnited States, is

l. A flexible corrugated resistance unit comprising an insulatingmaterial having a resistance-conductor wound thereon.

2. A corrugated resistance unit comprising a flexible insulatingmaterial having a resistance-conductor wound-thereon.

3. A resistance-unit comprising an insulating material having aresistance-conductor wound thereon and secured thereto by inden tations.

4. A resistance unit comprising a sheet of flexible insulating materialhaving a resistance-conductor spirally wound thereon and locked theretoby corrugations.

5. A resistance unit comprising a web of flexible insulating materialtraversed by a resistance-conductor and stiffened by corrugations.

6. A resitance unit comprising a sheet of asbestos, aresistance-conductor wound thereon and secured thereto by corrugations.

7. A resistance unit comprising a sheet of asbestos having an iron stripwound thereon and provided with terminals, said sheet being corrugatedthroughout.

8. A resistance unit comprising a sheet of insulating material having aresistancc-strn) wound thereon, said unit being provided with groovesrunning in a substantially lonrob gitudinal direction of said strip-andengaging In witness whereof I have hereunto set my each turn thereof. iband this 11th day of July, 1905.

9. A resistance unit comprising a sheet of asbestos, an iron stripspirally Wound there- HARRY HEATH 5 on, said unit being provided withgrooves run- Witnesses:

ning in a substantially longitudinal direction JOHN A. MGMANUS, J12,

of said strip and engaging each turn thereof. 7 J OHN G. OALLAN

